1. Field of the Invention
This invention relates to an image forming unit and an image forming apparatus.
2. Description of Related Art
Image forming apparatuses such as printers, photocopiers, and facsimile machines, as exemplified by printers, conventionally include respective image forming units for black, cyan, magenta, and yellow, and LED heads, transfer units, and fixing devices, which are disposed corresponding to the respective image forming units. The image forming unit, each includes, such as, e.g., a photosensitive drum, a charge roller, a developing device, a cleaning blade, a toner container containing toner as a developer.
The developing device includes such as, e.g., a toner reservoir for temporarily reserving a toner supplied from the toner container, a developing roller disposed at the toner reservoir, a developing blade, and a toner supply roller. The toner reserved at the toner reservoir is supplied to the developing roller by the toner supply roller, and is made to a thin layer with the developing blade to form toner images. In the printers, the surface of the photosensitive drum uniformly charged with the charge roller is exposed by the LED heads to form electrostatic latent images, and the toner on the developing roller is attached to the electrostatic latent images. The electrostatic latent images are developed, and toner images are formed on the photosensitive drum. Subsequently, the toner images are transferred onto a paper by the transfer roller of the transfer unit, and are fixed to the paper with the fixing device to form images on the paper.
With a printer in which respective image forming units are detachably attached to a body of the printer, or namely an apparatus body, the toner is consumed as repeating image formations, and if the toner in the toner container is consumed totally, the image forming unit should be replaced with a bland new one.
In such an image forming apparatus, a stirring member is installed for stirring the toner in the toner reservoir (see, e.g., Japanese Application Publication No. 2011-99894 (A1)).
The image forming unit thus structured is required to have a stable toner stirring performance.